What is the difference between PET and PET/CT?

I need to know What is the difference between PET and PET/CT? Is it better to get the PET/CT?

Answer

James Metz, MD, OncoLink Editor-in-Cheif, responds:

A PET scan (positron emission tomography) looks at the biologic activity of a tumor, not the shape and size of a tumor. A CT scan give anatomic information like exact location, size, and shape of a tumor with its relationship to other structures. Most times, we now go with a combined PET/CT scan so that we obtain both the biologic activity overlayed with the anatomic structure. This gives us more information. Most institutions have moved to combined PET/CT to get the best information.